Abstract：
The role of MRI to estimate liver iron concentration (LIC) for identifying patients with iron overload and guiding the titration of chelation therapy is increasingly established for routine clinical practice. However, the existence of multiple MRI-based LIC quantification techniques limits standardization and widespread clinical adoption. In this article, we review the existing and widely accepted MRI-based LIC estimation methods at 1.5 T and 3 T: signal intensity ratio (SIR) and relaxometry (R2 and R2*) and discuss the basic principles, acquisition and analysis protocols, and MRI-LIC calibrations for each technique. Further, we provide an up-to-date information on MRI vendor implementations and available offline commercial and free software for each MRI-based LIC quantification approach. We also briefly review the emerging and advanced MRI techniques for LIC estimation and their current limitations for clinical use. Lastly, we discuss the implications of MRI-based LIC measurements on clinical use and decision-making in the management of patients with iron overload. Some of the key highlights from this review are as follows: 1) Both R2 and R2* can estimate accurate and reproducible LIC, when validated acquisition parameters and analysis protocols are applied, 2) Although the Ferriscan R2 method has been widely used, recent consensus and guidelines endorse R2*-MRI as the most accurate and reproducible method for LIC estimation, 3) Ongoing efforts aim to establish R2*-MRI as the standard approach for quantifying LIC, and 4) Emerging R2*-MRI techniques employ radial sampling strategies and offer improved motion compensation and broader dynamic range for LIC estimation. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 2.
摘要：
MRI评估肝铁浓度（LIC）对于识别铁超负荷患者和指导螯合疗法滴定的作用越来越为常规临床实践确立。然而,多种基于MRI的LIC定量技术的存在限制了标准化和广泛的临床应用.在这篇文章中,我们回顾了现有和广泛接受的基于MRI的1.5T和3T的LIC估计方法：信号强度比（SIR）和弛豫（R2和R2*），并讨论了基本原理，采集和分析协议，以及每种技术的MRI-LIC校准。Further,我们为每种基于MRI的LIC量化方法提供了有关MRI供应商实施的最新信息,以及可用的离线商业和免费软件.我们还简要回顾了用于LIC估计的新兴和先进的MRI技术及其当前临床应用的局限性。最后,我们讨论了基于MRI的LIC测量对铁超负荷患者治疗的临床应用和决策的影响.本综述的一些关键亮点如下：1）R2和R2*都可以估计准确且可重复的LIC，当应用经过验证的采集参数和分析协议时，2）尽管FerriscanR2方法已被广泛使用，最近的共识和指南认可R2*-MRI是LIC估计的最准确和可重复的方法，3)持续的努力旨在建立R2*-MRI作为量化LIC的标准方法，和4）新兴的R2*-MRI技术采用径向采样策略，并为LIC估计提供改进的运动补偿和更宽的动态范围。证据水平：1技术效率：第2阶段。
